DESCRIPTION: This application addresses two major current themes in the epidemiology and prevention of adult mental disorders: a) social and economic disparities in health status: and b) early origins of adult health status. Where most of the current work in these areas has focused on physical health conditions (e.g., cardiovascular illness. diabetes) there is mounting evidence of the relevance of these lines of inquiry to psychiatric disorders. Furthermore, while socioeconomic disparities in depression in adulthood have been documented consistently, the mechanisms generating these disparities have yet to be fully elucidated. Accordingly, we seek to conduct new data analyses examining socioeconomic disparities in major depressive disorder in relation to adult and childhood socioeconomic status, and to examine the role of other childhood environmental factors in the development of depression. These investigations will be based on the Providence follow-up National Collaborative Perinatal Project, a thirty-year, longitudinal study of 1,263 individuals who were enrolled at birth and systematically followed for an average of 27.8 years. Comprehensive prospective assessment of childhood environmental conditions have been obtained at multiple points in time and adult psychiatric diagnoses obtained using structured diagnostic interviews. We will employ a range of analytic strategies including discrete-time survival analyses. The specific aims of this study are to examine the effects of childhood socioeconomic status on the occurrence and severity of major depressive disorder in adulthood. Furthermore, we will assess the direct role of childhood environmental factors in the occurrence of depression as well as their potential to mediate the association between early-life socioeconomic conditions and subsequent depression. Finally, we will study the risk that substance abuse disorders pose on the incidence of depression and examine whether this risk is modified by childhood conditions. The prospective nature of this study, the comprehensive assessment of parental and childhood variables, and the rigorous measurement of psychiatric disorders in adulthood make this sample uniquely suited to addressing these aims.